Experimental and theoretical structural study of ( 3E, 5E)-3,5-bis-(benzylidene)-4-oxopiperidinium mono- and ( 3E, 5E)-3,5-bis-(4- N, N-dialkylammonio)benzylidene)-4-oxopiperidinium trications (original) (raw)
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Molecules, 2013
The analysis of the IR carbonyl bands of some 3-(4′-substituted phenylsulfanyl)-1-methyl-2-piperidones 1-6 bearing substituents: NO 2 (compound 1), Br (compound 2), Cl (compound 3), H (compound 4) Me (compound 5) and OMe (compound 6) supported by B3LYP/6-31+G(d,p) and PCM calculations along with NBO analysis (for compound 4) and X-ray diffraction (for 2) indicated the existence of two stable conformations, i.e., axial (ax) and equatorial (eq), the former corresponding to the most stable and the least polar one in the gas phase calculations. The sum of the energy contributions of the orbital interactions (NBO analysis) and the electrostatic interactions correlate well with the populations and the ν CO frequencies of the ax and eq conformers found in the gas phase. Unusually, in solution of the non-polar solvents n-C 6 H 14 and CCl 4 , the more intense higher IR carbonyl frequency can be ascribed to the ax conformer, while the less intense lower IR doublet component to the eq one. The same ν CO frequency trend also holds in polar solvents, that is ν CO (eq) < ν CO (ax). However, a reversal of the ax/eq intensity ratio occurs going from non-polar to polar solvents, with the ax conformer component that OPEN ACCESS H [o-Ph] hydrogen bond that takes place in the ax conformer partially hinders the approach of the solvent molecules to the carbonyl oxygen atom. Therefore, the larger solvation that occurs in the carbonyl oxygen atom of the eq conformer is responsible for the observed and calculated decrease of the corresponding frequency. The X-ray single crystal analysis of 2 indicates that this compound adopts the most polar eq geometry in the solid. In fact, in order to obtain the largest energy gain, the molecules are arranged in the crystal in a helical fashion due to dipole moment coupling along with C-H … O and C-H … π Ph hydrogen bonds.
ACS Omega, 2020
The organic compounds with a π-bond system lead to electric charge delocalization which enables them to reveal fascinating nonlinear optical properties. Mono-carbonyl curcuminoids also have an appealing skeleton from the conjugation view point. Interesting chemical structures of the 3,5-bis(arylidene)-Nbenzenesulfonyl-4-piperidone derivatives motivated us to perform density functional theory (DFT)-based studies. Therefore, computations using the B3LYP/6-311G(d,p) functional of DFT were executed to explore geometric parameters, highest occupied molecular orbital (HOMO)−lowest unoccupied molecular orbital (LUMO) energies, and natural bond orbital (NBO) analyses. Moreover, three different functionals such as HF, B3LYP, and M06 with the 6-311G(d,p) basis set were used to investigate the average polarizability ⟨α⟩ and first hyperpolarizability (β tot)-based properties of all compounds. A good concurrence among calculated and experimental parameters was obtained through root mean square error calculations. The molecular stability of piperidone derivatives was examined using the Hirshfeld surface and NBO analyses. Natural population analysis was also performed to obtain insights about atomic charges. Calculated HOMO−LUMO energies showed that charge transfer interactions take place within the molecules. Moreover, global reactivity parameters including electronegativity, chemical hardness, softness, ionization potential, and electrophilicity were calculated using the HOMO and LUMO energies. The average polarizability ⟨α⟩ and first hyperpolarizability (β tot) values of all compounds were observed to be larger in magnitude at the aforesaid functional than the standard compound.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013
This work presents the characterization of (2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl)piperidine-3,4,5-triol (abbreviated as HEHMPT) by quantum chemical calculations and spectral techniques. The spectroscopic properties are investigated by FT-IR, FT-Raman and UV-Vis techniques. The FT-IR and FT-Raman spectra of the title compound have been recorded in the region 4000-400 cm-1 and 4000-100 cm-1 respectively. The UV-Vis absorption spectrum of the HEHMPT that dissolved in water is recorded in the range of 100-400 nm. The structural and spectroscopic data of the molecule are obtained from B3LYP and M06-2X with 6-31G(d,p) basis set calculations. The theoretical wavenumbers are scaled and compared with experimental FT-IR and FT-Raman spectra. The complete assignments are performed on the basis of the normal coordinate analysis (NCA), experimental result and potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method, interpreted in terms of fundamental modes. The stable geometry of the compound has been determined from the potential energy surface scan. The stability of molecule is analyzed by NBO analysis. The molecule orbital contributions are studied by using the total (TDOS), partial (PDOS), and overlap population (OPDOS) density of states. The electronic properties like UV spectral analysis and HOMO-LUMO energies are reported. The calculated HOMO and LUMO energies show that charge transfer interactions taking place within the molecule. Mulliken population analysis on atomic charges is also calculated.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014
h i g h l i g h t s IR, Raman, NBO analysis and MEP were reported. The wavenumbers are calculated theoretically using Gaussian09 software. The wavenumbers are assigned using PED analysis. The geometrical parameters are in agreement with the reported literature.
Structural investigation on three 3,5-trans disubstituted piperidines. X-ray and theoretical studies
Journal of Molecular Structure: THEOCHEM, 2002
Three different 3,5-trans disubstituted piperidine derivatives, namely 1 (3R,5R )-1-benzyl-piperidine-3,5-diol, 2 (3R,5R )-1benzyl-1-oxy-piperidine-3,5-diol and 3 (3R,5R )-1-benzyl-3,5-difluoro-piperidine 1-oxide were studied by using both experimental and theoretical methods. Solid state X-ray structures of all the molecules are presented. Structural differences and analogies in the piperidine rings are discussed in terms of intramolecular H-bond and non-bonded repulsions. In addition, the H-bonding pattern in each crystal packing is discussed in view of the hydroxy groups orientation. The geometrical parameters from ab initio calculations performed on simplified models of the studied molecules, in the gas phase, were also discussed. Finally, in all cases, attention was paid to the energetics of the experimentally isolated conformational isomer and to that obtained as the results of the ring and/or nitrogen inversion. q
International Journal of Advanced Chemistry, 2017
The molecular structure and conformational aspects of 3t-pentyl-2r,6c-di(naphthalen-1-yl)piperidin-4-one oxime (3-PDNPO) were studied by using B3LYP level with 6-31G(d,p) p basis set. The optimized geometrical parameters are in agreement with analogue available single XRD data. The optimized parameters showed that the piperidin-4-one ring adopts chair conformation.The FT- IR and FT-Raman spectra were recorded within the region 4000-400 cm-1 and 4000-10 cm-1, respectively. It was found by experimental wavenumbers and DFT wavenumbers were in good agreement. Electronic properties are investigated using TD-DFT/B3LYP method using 6-31G (d,p) basis set and compared with experimental UV-visible spectra. Additionally, the ΔE gap investigated three phases follows the order of CHCl3…
In the section based on DFT calculations of this study, all calculations were carried out using DFT/B3LYP method with 6-311G(d,p) basis sets of Gaussian program . Optimization of synthesized molecules was performed with the help of 6-311G (d,p) basis set, because this basis set is known as one of the basis sets that gives more accurate results in terms of the determination of geometries and electronic properties for a wide range of organic compounds. Quantum chemical parameters such as the energy of the highest occupied molecular orbital (E HOMO ), the energy of the
Acta Crystallographica Section E Crystallographic Communications, 2015
The crystal structures of the two title piperidine derivatives show different conformations for the six-membered heterocycle. TheN-substituted 4-piperidinone 1-[(1R)-2-hydroxy-1-phenylethyl]piperidin-4-one, C13H17NO2, (I), has a chair conformation, while the piperidine substituted in position 2 with a thiocarbonyl group, 8-[(1S)-1-phenylethyl]-1,4-dioxa-8-azaspiro[4.5]decane-7-thione, C15H19NO2S, (II), features a half-chair conformation. Comparison of the two structures, and data retrieved from the literature, suggests that the conformational flexibility is mainly related to the hybridization state of the C atom α to the piperidinic N atom: a Csp3atom favours the chair conformer, while a Csp2atom distorts the ring towards a half-chair conformer. In the crystal structure of (I), weak C—H...O hydrogen bonds link the molecules into supramolecular chains propagating along theb-axis direction. In the crystal of (II), the molecules are linked by weak C—H...S contacts into supramolecular c...
Journal of Molecular Structure 1128 (2017) 636-
a b s t r a c t (2E)-3-(3,4-dimethoxyphenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (DMHP) was synthesized by the reaction of 3,4-dimethoxy benzaldehyde with 1-(2-hydroxyphenyl) ethanone under microwave irradiation. The structure of DMHP was established experimentally by EI-MS, FT-IR, 1 H and 13 C NMR spectral studies and elemental analysis and theoretically. Electronic absorption and emission spectra of DMHP were studied in different solvents on the basis of polarities, and the obtain data were used to determine the solvatochromic properties such as extinction coefficient, oscillator strength, transition dipole moment, stokes shift, fluorescence quantum yield and photochemical quantum yield. The absorption and emission maxima were red-shifted when the polarity of the solvent was increased from dioxan to DMSO; in excellent agreement the DFT findings. The DMHP experimental intramolecular charge transfer (ICT) was complemented by a natural bond orbital (NBO) analysis. Fluorescence intensities of DMHP were increase and decrease in presence of CTAB and SDS, so DMHP was used to find out the critical micelle concentration (CMC) of CTAB and SDS.